Amperometric determination of ascorbic acid in real samples using an aluminum electrode, modified with nickel hexacyanoferrate films by simple electroless dipping method

Nickel hexacyanoferrate (NiHCNF) film modified Al electrode prepared by simple and rapid electroless dipping procedure was used for the mediated oxidation of ascorbic acid. The anodic peak current observed in cyclic or linear sweep voltammetry was linearly dependent on the ascorbic acid concentration. At a fixed potential under hydrodynamic conditions (stirred solutions), the calibration plot was linear over the ascorbic acid concentration range 2 x 10(-6) - 2 x 10(4) M. The detection limit of the method is 2 x 10(6) M, low enough for trace ascorbic acid determination in various real samples. The proposed method was used for determination of ascorbic acid in fresh fruit juices, vegetables, pharmaceutical preparations and blood plasma. The results obtained are in good agreement with those obtained by the official standard methods. The analysis with NiHCF-film-niodified Al electrode was selective for ascorbic acid from the various concomitant reducing compounds in real samples.